Add Interop Start timestamp to CrossL2Inbox (ethereum-optimism#11398)

* add interop start timestamp to CrossL2Inbox with tests

* change to function, add assertions, update tests

* correct the preimage of interop start storage slot

* rename custome error

* require id timestamp must be > interopStartTime not >=, update tests to use realistic interopStartTime (non-zero)

* bump CrossL2Inbox semver, run just semver-lock & just snapshots

* add natspec for setInteropStart

* update semver lock

Author: AmadiMichael

packages/contracts-bedrock/semver-lock.json

@@ -68,8 +68,8 @@
     "sourceCodeHash": "0x3a725791a0f5ed84dc46dcdae26f6170a759b2fe3dc360d704356d088b76cfd6"
   },
   "src/L2/CrossL2Inbox.sol": {
-    "initCodeHash": "0x80124454d2127d5ff340b0ef048be6d5bf5984e84c75021b6a1ffa81703a2503",
-    "sourceCodeHash": "0xfb26fc80fbc7febdc91ac73ea91ceb479b238e0e81804a0a21192d78c261a755"
+    "initCodeHash": "0x071b53cd8cf0503af856c4ee0ee34643e85059d53c096453891225472e02abfa",
+    "sourceCodeHash": "0x3c78129b91d9f06afa4787d4b3039f45a3b22b3edf5155ed73d4f0c3ab33c6c8"
   },
   "src/L2/ETHLiquidity.sol": {
     "initCodeHash": "0x98177562fca0de0dfea5313c9acefe2fdbd73dee5ce6c1232055601f208f0177",

packages/contracts-bedrock/snapshots/abi/CrossL2Inbox.json

@@ -75,6 +75,19 @@
     "stateMutability": "payable",
     "type": "function"
   },
+  {
+    "inputs": [],
+    "name": "interopStart",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "interopStart_",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
   {
     "inputs": [],
     "name": "logIndex",
@@ -101,6 +114,13 @@
     "stateMutability": "view",
     "type": "function"
   },
+  {
+    "inputs": [],
+    "name": "setInteropStart",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
   {
     "inputs": [],
     "name": "timestamp",
@@ -218,6 +238,11 @@
     "name": "ExecutingMessage",
     "type": "event"
   },
+  {
+    "inputs": [],
+    "name": "InteropStartAlreadySet",
+    "type": "error"
+  },
   {
     "inputs": [],
     "name": "InvalidChainId",
@@ -228,6 +253,11 @@
     "name": "InvalidTimestamp",
     "type": "error"
   },
+  {
+    "inputs": [],
+    "name": "NotDepositor",
+    "type": "error"
+  },
   {
     "inputs": [],
     "name": "NotEntered",

packages/contracts-bedrock/src/L2/CrossL2Inbox.sol

@@ -17,6 +17,12 @@ interface IDependencySet {
     function isInDependencySet(uint256 _chainId) external view returns (bool);
 }
 
+/// @notice Thrown when the caller is not DEPOSITOR_ACCOUNT when calling `setInteropStart()`
+error NotDepositor();
+
+/// @notice Thrown when attempting to set interop start when it's already set.
+error InteropStartAlreadySet();
+
 /// @notice Thrown when a non-written transient storage slot is attempted to be read from.
 error NotEntered();
 
@@ -35,6 +41,10 @@ error TargetCallFailed();
 /// @notice The CrossL2Inbox is responsible for executing a cross chain message on the destination
 ///         chain. It is permissionless to execute a cross chain message on behalf of any user.
 contract CrossL2Inbox is ICrossL2Inbox, ISemver, TransientReentrancyAware {
+    /// @notice Storage slot that the interop start timestamp is stored at.
+    ///         Equal to bytes32(uint256(keccak256("crossl2inbox.interopstart")) - 1)
+    bytes32 internal constant INTEROP_START_SLOT = 0x5c769ee0ee8887661922049dc52480bb60322d765161507707dd9b190af5c149;
+
     /// @notice Transient storage slot that the origin for an Identifier is stored at.
     ///         Equal to bytes32(uint256(keccak256("crossl2inbox.identifier.origin")) - 1)
     bytes32 internal constant ORIGIN_SLOT = 0xd2b7c5071ec59eb3ff0017d703a8ea513a7d0da4779b0dbefe845808c300c815;
@@ -55,15 +65,42 @@ contract CrossL2Inbox is ICrossL2Inbox, ISemver, TransientReentrancyAware {
     ///         Equal to bytes32(uint256(keccak256("crossl2inbox.identifier.chainid")) - 1)
     bytes32 internal constant CHAINID_SLOT = 0x6e0446e8b5098b8c8193f964f1b567ec3a2bdaeba33d36acb85c1f1d3f92d313;
 
+    /// @notice The address that represents the system caller responsible for L1 attributes
+    ///         transactions.
+    address internal constant DEPOSITOR_ACCOUNT = 0xDeaDDEaDDeAdDeAdDEAdDEaddeAddEAdDEAd0001;
+
     /// @notice Semantic version.
-    /// @custom:semver 1.0.0-beta.4
-    string public constant version = "1.0.0-beta.4";
+    /// @custom:semver 1.0.0-beta.5
+    string public constant version = "1.0.0-beta.5";
 
     /// @notice Emitted when a cross chain message is being executed.
     /// @param msgHash Hash of message payload being executed.
     /// @param id Encoded Identifier of the message.
     event ExecutingMessage(bytes32 indexed msgHash, Identifier id);
 
+    /// @notice Sets the Interop Start Timestamp for this chain. Can only be performed once and when the caller is the
+    /// DEPOSITOR_ACCOUNT.
+    function setInteropStart() external {
+        // Check that caller is the DEPOSITOR_ACCOUNT
+        if (msg.sender != DEPOSITOR_ACCOUNT) revert NotDepositor();
+
+        // Check that it has not been set already
+        if (interopStart() != 0) revert InteropStartAlreadySet();
+
+        // Set Interop Start to block.timestamp
+        assembly {
+            sstore(INTEROP_START_SLOT, timestamp())
+        }
+    }
+
+    /// @notice Returns the interop start timestamp.
+    /// @return interopStart_ interop start timestamp.
+    function interopStart() public view returns (uint256 interopStart_) {
+        assembly {
+            interopStart_ := sload(INTEROP_START_SLOT)
+        }
+    }
+
     /// @notice Returns the origin address of the Identifier. If not entered, reverts.
     /// @return Origin address of the Identifier.
     function origin() external view notEntered returns (address) {
@@ -140,7 +177,7 @@ contract CrossL2Inbox is ICrossL2Inbox, ISemver, TransientReentrancyAware {
     ///         is in the destination chain's dependency set.
     /// @param _id Identifier of the message.
     function _checkIdentifier(Identifier calldata _id) internal view {
-        if (_id.timestamp > block.timestamp) revert InvalidTimestamp();
+        if (_id.timestamp > block.timestamp || _id.timestamp <= interopStart()) revert InvalidTimestamp();
         if (!IDependencySet(Predeploys.L1_BLOCK_ATTRIBUTES).isInDependencySet(_id.chainId)) {
             revert InvalidChainId();
         }

packages/contracts-bedrock/src/L2/ICrossL2Inbox.sol

@@ -13,6 +13,10 @@ interface ICrossL2Inbox {
         uint256 chainId;
     }
 
+    /// @notice Returns the interop start timestamp.
+    /// @return interopStart_ interop start timestamp.
+    function interopStart() external view returns (uint256 interopStart_);
+
     /// @notice Returns the origin address of the Identifier.
     /// @return _origin The origin address of the Identifier.
     function origin() external view returns (address _origin);
@@ -44,4 +48,12 @@ interface ICrossL2Inbox {
     )
         external
         payable;
+
+    /// @notice Validates a cross chain message on the destination chain
+    ///         and emits an ExecutingMessage event. This function is useful
+    ///         for applications that understand the schema of the _message payload and want to
+    ///         process it in a custom way.
+    /// @param _id      Identifier of the message.
+    /// @param _msgHash Hash of the message payload to call target with.
+    function validateMessage(Identifier calldata _id, bytes32 _msgHash) external;
 }